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PN mini-submarine fleet

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old italian origin sub .. now retired

n the late 1960s, Pakistan ordered six SX-404s to a slightly modified design. The Pakistani Navy deployed its six boats against the Indian Navy during the 1971 war. One of them, reportedly fitted with external torpedo tubes fired on an Indian naval frigate, INS Kukri, but the torpedo remained stuck in its external launcher. Of the six, one was lost with all hands as a result of an accident on December 27, 1976. Following removal from service, four were scrapped and one was placed ashore as an exhibit in the Pakistan Maritime Museum in Karachi.

Thank you for the interesting history. I thought it was a full sized submarine in the Kukri engagement guess I learnt something new today. Would be interesting if a slightly larger coastal submarine can be engineered cheaply and locally.
 
Was just reading the H. I. Sutton website and how mine laying submarines bagged the largest number of enemy ships yet are the least known submarines as their work was not particularly "heroic" or "fashionable".
http://www.hisutton.com/German-WW1-Type-UC-1-U-Boat.html

The UC II had the highest number of kills of any platform. Imagine that. These are very simple submarines that don't need long duration on station, as they are not ambushing anything. They simply go to a shipping lane / outside a port and deploy mines, come back.

Doesn't need AIP, doesn't need much but the deadliest ships. What if Pakistan designed a UC II type submarine today? 400 tons, 18 mines, 6 crew, 2 torpedoes for self defense. India's Eastern coast would be in deep trouble.

Such small submarines would be difficult to spot even on sonar. They are a lot less vulnerable due to them not needing to stay on station. If Pak had say 10 such boats, they could deploy hundreds of mines along the Indian coast in a handful of days.
 
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(USS Diablo in 1964, after the Fleet Snorkel Conversion and just before the submarine transferred to Pakistan. This photo gives a good view of the plexiglass bridge windshield which was later recovered off the wreck.)

USS Diablo underwent the conversion in 1963. As modified, USS Diablo displaced 1,570t surfaced and 2,414t submerged. The refitted submarine could make 20kts surfaced, 12kts snorkeling with the diesels, or 8 ¾kts submerged on battery power. The underwater endurance on battery power remained limited; 97NM at 2kts or 48 hours maximum. USS Diablo now had a crew of 76 (9 officers and 68 enlisted men). The submarine carried the SS-2 radar with an average range of 21NM, the AN/BLR-6 ESM system, and AN/BQR-2 sonar with a range of 4 NM.

The armament of USS Diablo in postwar American (and later, Pakistani) service remained the WWII-era Mk14 torpedo. The Mk14 was the main US Navy submarine torpedo of WWII. It had a range of 2 ¼NM at 46kts or 4 ½NM at 30kts, and had a 507 lbs TNT warhead. This was an unguided, straight-running torpedo inferior to the post-WWII homing designs. None the less, because of the huge quantity built, it remained in frontline US Navy use through the Korean War and in second-line service into the 1970s. The Mk14 was always the torpedo type included with exported American WWII-veteran submarines.

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(The WWII-era Mk14 which was heavily exported after the war and used in the US Navy until the early 1970s.)

Transfer to Pakistan

In 1963, USS Diablo was loaned to Pakistan on a four-year basis under terms of the Security Assistance Program (SAP) with an option to renew or purchase afterwards. On 1 June 1964, the Pakistani ensign was raised and USS Diablo became PNS Ghazi.

USS Diablo was selected as the freshly-done Fleet Snorkel upgrade would give the Pakistani navy a quality asset, but would not take one of the more valuable GUPPY-upgraded WWII submarines out of American use.

PNS Ghazi arrived at her new home port of Karachi, Pakistan in September 1964.
PNS Ghazi was Pakistan’s first-ever submarine.

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(PNS Ghazi arrives at Karachi, Pakistan in September 1964.)

THE 1965 WAR

The 1965 Indo-Pakistani War was the culmination of several border disputes. The war started on 5 August 1965. PNS Ghazi was assigned to patrol south of West Pakistan, and ordered to seek out only “major” Indian warships, understood to be carriers, cruisers, and possibly large destroyers. India tried throughout the war to de-escalate the conflict and limit it as much as possible to a regional ground war. As such, PNS Ghazi‘s prime target; the aircraft carrier INS Vikrant; was not to be found.

(INS Vikrant had been launched as HMS Hercules by Great Britain during WWII but left unfinished when WWII ended. The incomplete carrier was later bought by India and finished to Indian specifications.)

The Indian navy was on the lookout of PNS Ghazi and the submarine had to be wary of detection. On 9 September, the Indian frigate INS Beas made an unsuccessful depth charge attack. Later an Indian Alize ASW plane flew directly over PNS Ghazi while the submarine had the snorkel mast and periscope exposed. It was a miracle that the plane didn’t detect the submarine.



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(The cramped control room of PNS Ghazi.)


On 17 September 1965, PNS Ghazi acquired a surface contact which was identified as the frigate INS Brahmaputra, one of the Indian navy’s more modern warships at the time. PNS Ghazi fired three WWII-era Mk14 torpedoes at the contact and increased depth to evade counter-attack. According to the submarine’s logs, three distinct explosions were heard at the time the torpedoes should have impacted, and PNS Ghazi was credited with sinking INS Brahmaputra.

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(A photo taken inside PNS Ghazi’s engine room during the 1965 war. The Fleet Snorkel-converted submarines retained their WWII propulsion system, four Fairbanks-Morse diesel engines and two Elliot electric motors.)


In fact, INS Brahmaputra was not sunk, and had not even been hit. The frigate never acquired either a submarine nor incoming torpedoes, and had not dropped any depth charges. No ships were damaged or sunk in the area. It’s unknown to this day what PNS Ghazi‘s target was or what the three explosions were.

The war ended on 23 September 1965 and PNS Ghazi was recalled to Karachi.

Refit in Turkey


The USA placed a weapons embargo on Pakistan in 1965. PNS Ghazi badly needed a refit at that time. To circumvent the embargo, Pakistan negotiated a shipyard deal with Turkey. Turkish shipyards were well familiar with WWII-vintage American submarines as the Turkish navy was operating several. Moreover, in 1953 Gölcük Shipyard in Turkey had been provided the Fleet Snorkel blueprints and had actually done two Fleet Snorkel conversions, on TCG Gür and TCG Inonu (formerly USS Chub and USS Brill during WWII) which had transferred unmodified in 1948. The refit cost $1.5 million ($11.1 million in 2015 dollars) which was a fairly good bargain.

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(PNS Ghazi in Karachi harbor in 1970, following the Turkish refit.)

Because the Suez Canal was still closed from the Arab-Israeli Six Day War, PNS Ghazi had to go the long way around South Africa and up through the Atlantic. The refit started in March 1968 and was completed in April 1970. It’s believed that the WWII American mines PNS Ghazi used in 1971 were bought “under the table” from Turkey at this time.
 
These boats don't have names since they are not actually commissioned units. They're known as X-Craft 01,02 & 03.
One of these was lost with all hands at sea during an SSGN training mission in 1994-95. The entire crew (15 men) made a 'wet' escape through the main hatch from a depth of about 30 meters.
The submarine was later raised in the PN's first submarine salvage operation in mid-1995. It was overhauled and returned to service a few years later and remains in service to this day.
 
CORRECTION PLEASE: The 110 ton X-Craft supplied to PN by COSMOS of Italy in late 80's is NOT A SWAT Submarine. SWAT's are from 500-700 tons. The PN X-Crafts are now very old, overhauled many times with the original manufacturer COSMOS gone out of business. These are used primarily by SSGN for covert ops

So whats the progress now?
 
I'm sure PN is making Chinese ones at home but they should also get license for EU ones too.
 
One thing that came to my mind for a while about mini subs is underwater glider concept. it just surfaces and takes in water and the wings do the rest gliding the mini submarine.


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No propeller and possbly almost no noise. It can go very long distances compared to normal propellers.

This one for example has recharge option and can glide 3000kms.



Only downside would be it is slower than normal propeller submarines. You can install propeller as well when you want the drone to follow the target for example moving ships and send back the location data for you to target the ships.
If you install a passive sonar on it it can patrol in a large area. When it detects the target it can go active sonar and use normal propeller to follow the target and send back continious target data be it enemy submarines or ships.
 
The PN should look at deeper diving mini-submarines (as they could hide in key sea lanes, but well below other standard attack submarine depths), and use the advantage of newer battery technology to just stay on station (such as outside our ports, and littoral sea lanes) for a couple of weeks at a time; until relieved by another submarine.

In this way, the submarine could help maintain a “bastion” in our littoral coastline, and act as an early line of defense from attack from the sea.

Used in coordination with gliders and a Sosus net, it could take the burden off of longer range submarines; which could use those resources to better take the fight to the enemy
 
The PN should look at deeper diving mini-submarines (as they could hide in key sea lanes, but well below other standard attack submarine depths), and use the advantage of newer battery technology to just stay on station (such as outside our ports, and littoral sea lanes) for a couple of weeks at a time; until relieved by another submarine.

In this way, the submarine could help maintain a “bastion” in our littoral coastline, and act as an early line of defense from attack from the sea.

Used in coordination with gliders and a Sosus net, it could take the burden off of longer range submarines; which could use those resources to better take the fight to the enemy

But they are deployed by large ships or subamrines. PN I guess building 6 or 8 Mini Submarines like the Chinese ones and I'm sure they are also building some with Turkey. :pakistan: :turkey:
 
But they are deployed by large ships or subamrines. PN I guess building 6 or 8 Mini Submarines like the Chinese ones and I'm sure they are also building some with Turkey. :pakistan: :turkey:

Sure, deploy them by a larger submarine or quietly by a submarine tender and have the submarine be recovered similarly. Something akin to the soviet “Piranha” class.

a couple of torpedo tubes with advanced Torpedos or advanced anti-ship cruise missiles and the ability to dive deep, to carry out a hit and run attack. The run part would be dictated by the capabilities of the propulsion; hence the need to explore modern battery technology. If the propulsion technology is there to allow a modest sprint at high speed after an attack, it might be a viable option to guard the coast and sea lanes, while the large subs can focus on offensive operations.

There small size would allow keep costs low; a fraction of the cost of the planned Hangor Class, but with just the right punch to be a coastal defense force. Like a “picket sub”. Might even work as an unmanned platform and get the attention of the Chinese navy, for their potential Taiwan invasion protection requirement.

 
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These should be scrapped.
Turkish STM started designing a mini submarine for the Pakistani navy to replace 3 Italian Cosmos MG110 class miniature submarines that where commissioned in 1993

Cosmos MG110 (110 tonnes)
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Where are CGIs for the Turkish STM mini-submarine? I am sure PN is involved in the R&D with Turkey over submarines:
  • Mini-Submarines
  • SSK Class Submarines
  • SSN Submarines (may be in future)
 

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